1. Field of the Invention
The present invention relates to an automotive air conditioner in which the operation of a refrigerant compressor is controlled based on the temperature of a refrigerant evaporator or on the temperature of air immediately after the air has been cooled by the refrigerant evaporator.
2. Description of the Related Art
In a conventional automotive air conditioner, in order to prevent the reversal of liquid occurring in conjunction with the frosting of a refrigerant evaporator (in order to prevent the compression of liquid in a refrigerant compressor), a thermistor thermometer is disposed at an air downstream side of the refrigerant evaporator, so that the operation of the refrigerant compressor is ON/OFF controlled based on an air temperature (a lowest temperature of the refrigerant evaporator) that has been detected by the thermistor thermometer so disposed (refer to Japanese Patent No. 2769073).
As a single thermistor thermometer is used in the related art, the thermistor thermometer needs to be disposed so as to correspond to a lowest temperature location of the refrigerant evaporator in order to detect the frosting of the refrigerant evaporator in an early stage. However, as the lowest temperature location of a refrigerant evaporator differs depending on the type of refrigerant evaporators used (depends on the model), it has been necessary to determine the location of a temperature thermistor by carrying out many conformance tests for each model.
In addition, even if the mounting position of a thermistor thermometer is determined by conformance tests, it is not possible to prove that the mounting position so determined corresponds to the lowest temperature of the thermistor thermometer. Due to this, in an automotive air conditioner in which temperature and humidity conditions are wide and, moreover, the discharge flow rate of a refrigerant compressor varies at all times, it has been necessary to set a large safety factor in the control thereof, resulting in a risk of insufficient cooling performance.